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Introduction to Scanning
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Last changed: March 27, 1995. |
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Introduction to Scanning
by Bob Parnass, AJ9S
[NOTES: This article may not be reproduced in whole or in
part on CDROMS, in bulletin boards, networks, or
publications which charge for service without permission of
the author. Free distribution is encouraged.]
This introduction is intended for people new to the
scanning hobby and is oriented to scanning in the USA. It
tells where you can buy your first scanner, what features
it should have, where to get it repaired if required, how
to get frequency information, and mentions a few scanner
clubs worth joining.
The author writes a monthly "Scanner Equipment" column for
Monitoring Times magazine, published by Grove Enterprises,
but views expressed in this article are his own.
Why Scanning?
Every day and night, scanner hobbyists are entertained by
what they overhear on their radios. Police cars, fire
engines, ambulances, armored cars, trains, taxis,
airplanes, and buses are all equipped with radios and you
can listen to them. You can monitor the local sheriff and
fire departments to hear about events "as they happen,"
before the news reporters hear about them. Hostage dramas,
bank robberies, car crashes, chemical spills, tornado
sightings are all fair game. In a single afternoon, you
can hear a high speed police chase, Drug Enforcement agents
on a sting operation, and undercover FBI agents as they
stakeout a suspect.
How about listening to a presidential candidate discuss
strategy with his advisor from a 415 MHz radiophone in Air
Force 1, or a team of G-men protect him while transmitting
in the 167 MHz range?
Baby monitor intercoms are actually transmitters and you
can hear them between 49.67 and 49.99 MHz.
Stay ahead of road conditions by listening to highway road
crews, snow plows, and traffic helicopter pilots.
Take your scanner to sporting events and listen to race car
drivers, football coaches, etc., in the 151, 154, and 468
MHz ranges.
Monitor the everyday hustle and bustle of businesses, from
cable TV repair crews tracking down pirate descrambler
boxes, to security guards at your nuclear power plant or
mall security guards chasing a shoplifter.
You can even listen to the order taker's wireless
microphone at the local McDonald's restaurant on 154.6 and
35.02 MHz!
Is Scanning Legal?
In the United States, scanning from your home or at work is
perfectly legal in most situations. The Electronic
Communications Privacy Act of 1986 made it illegal to
listen to mobile phones, common carrier paging, and a few
other types of communication. A new law outlaws listening
to cordless phones, too, but many scanners cover these
frequencies, and it's clear that Americans still listen to
whatever they want in the privacy of their own homes
despite the laws.
It is now illegal for companies to sell recently
manufactured scanners which cover or can be easily modified
to cover the cellular phone frequencies, but sales by
private individuals will still be allowed.
Speaking of privacy, federal law also requires you to keep
what you hear to yourself and not use the information you
hear on your scanner for personal gain.
Be aware that several states have laws pertaining to
scanning while in your car. Indiana restricts some
portable scanners. A few states have enacted their own
laws against listening to cordless phones. You can find
out about these restrictions in a 39 page paperback, ANARC
Guide to U. S. Monitoring Laws, compiled by Frank
Terranella, available for $9.95 + shipping from Grove
Enterprises, PO Box 98, Brasstown, NC 28902.
What Scanner Should I Buy?
Radio Shack and Uniden (maker of Bearcat, Regency, and
Cobra brands) offer a wide choice of scanners. Radio Shack
scanners bear the Realistic label but are actually
manufactured by both GRE (General Research Electronics) and
by Uniden. Personally, I don't recommend Trident nor many
of the AOR brand scanners, although the AR8000 and AR3000
have good reputations.
Programmable (synthesized) units have replaced crystal
controlled models as they don't require crystals and
usually have a keypad that permits you to store frequencies
into channels. Programmables are now so cheap it doesn't
make sense to buy a crystal unit as your main scanner
unless you get it for under $45 or so.
You can get a battery operated hand held scanner, a bigger
"base" scanner which is powered from an AC outlet, or a
mobile scanner which connects to your auto's electrical
system. There are tradeoffs -- base and mobile scanners
have larger displays and almost always provide more audio
than portables, and some portables are more prone to
interference when connected to outdoor antennas than base
models. But when severe weather knocks out the power in
your home, there's nothing like having a battery operated
scanner to monitor the power utility and police
frequencies!
Make sure your first scanner:
1. has a "search" feature, which allows it to search all
the frequencies between two frequency limits of your
choosing. The lowest cost programmables can't search.
2. covers the 800 MHz band. Usage of the 800 - 950 MHz
band is growing fast and you will miss out on the
action unless your scanner covers this band.
If you're not sure whether you'll like scanning, don't want
to spend much money, a 40 channel radio will do. In
general, the more channels and banks, the better.
Most of the action takes place on frequencies between 30
and 1000 MHz, so don't be misled by scanner models boasting
coverage from 3 to 2000 MHz. There's currently not much to
monitor in the 1000 - 2000 MHz range.
If you are interested in receiving short wave, that is,
signals in the 3 - 30 MHz range, it's best to get a short
wave radio specifically designed for that purpose.
Although some scanners receive the short wave band, their
performance in that range is often poor.
Deluxe scanners can be controlled by a personal computer,
although this feature isn't important to many scanner
owners.
Almost all low and mid-priced scanners are prone to
receiving images -- receiving the same signal erroneously
on two or more frequencies. With a few exceptions, images
are undesireable due to the interference they cause, e.g.,
hearing aircraft transmissions while the scanner is tuned
to the local police frequency. Premium quality scanners
use "up conversion" circuitry, a scheme which greatly
reduces image reception.
Currently, the more popular scanners include the
Uniden/Bearcat BC760XLT (a/k/a 950XLT) and discontinued
Radio Shack PRO-2006 base/mobiles, the Uniden/Bearcat
BC200XLT (a/k/a BC205XLT), BC220XLT, and Radio Shack PRO-43
portables. A number of owners report problems with the
Icom R1 portable and the older Uniden/Bearcat 8500XLT base
and 2500XLT portable. The new Uniden replacement models,
the BC9000XLT and BC3000XLT, work very well and are my
current favorites.
Considered by many as the best scanner ever made, the 400
channel Radio Shack PRO-2006 has recently been replaced by
the 1000 channel PRO-2035. The portable Radio Shack PRO-62
is a good performer. All three models employ up conversion
and are made for Radio Shack by GRE (General Research
Electronics). Both GRE and Uniden make scanners for Radio
Shack.
Scanner Antennas
All scanners come with a built in antenna, permitting
reception up to about 20 miles or so.
Portable scanners are supplied with a spring shaped
antenna, covered by rubber. Although it is small and
tolerant of physical abuse, the range of a heliflex antenna
is very limited. Augmenting it with a 19" telescoping
metal antenna can improve portable reception greatly.
Outdoor antennas, like the Channel Master 5094A or Antenna
Specialists AV-801 (recently discontinued), can extend
reliable reception to 100 miles or more. If you do use an
outdoor antenna, be sure to disconnect and ground it during
storms and when not in use to avoid a lightning hazard.
Discone and ground plane type antennas can be more prone to
lightning strikes because they are not at "DC ground."
Coaxial Cable Feedlines
If your antenna installation requires more than 50 feet of
feedline, use RG213/U or high quality RG8/U coaxial cable.
RG213/U has a non-contaminating jacket and will last
longer. Each has an outer diameter of about 13/32".
Similarly sized Belden 9913 cable and clones have lower
attenuation but are difficult to bend, require special
connectors, and can accumulate moisture inside because it
they are hollow.
If you must use a small diameter cable for long runs, use
RG6/U. Avoid RG58/U (7/32" OD) due to its losses at high
frequencies. RG8/X (1/4" OD) is suitable for short patch
cords.
Where Can I Buy A Scanner?
Almost every community has at least one Radio Shack store,
and you can find scanners there. Discount chain stores
like Wal-Mart, K-Mart, Service Merchandise, and Circuit
City sell scanners, but carry just a few models.
Department stores, like Sears Roebuck and Montgomery Wards,
sometimes offer low end scanners, although at high prices.
The best buys on new scanners are from reputable mail order
radio dealers, for example:
- Grove Enterprises, 300 S. Highway 64 West, Brasstown,
NC 28902. For a free catalog, call (704)837-9200.
Telephone (orders only): (800)438-8155.
- National Tower Company, PO Box 15417, Shawnee Mission,
KS 66215. Telephone (913)888-8864.
- The Ham Station, 220 N. Fulton Ave., Evansville, IN
47719-0522. Telephone (800)729-4373, (812)422-0231.
- Marymac Distributing (Katy, TX) sells Radio Shack
scanners at discount, but charges a 20% restocking fee
for returned merchandise. Telephone (800)231-3680 and
(713)392-0747.
- Scanner World (Albany, NY). Telephone (518)436-9606.
Beware of inflated "shipping and handling" charges and be
sure to include these when comparison shopping.
Many ham radio dealers, like Amateur Electronics Supply
(Milwaukee, WI, (800)558-0411), also sell scanners.
Used scanners may be found at hamfests, flea markets,
garage sales, or listed in the classified advertisement
section of your newspaper.
Modifying Your Scanner
If you are handy with a soldering iron, you may be
interested in modifying your scanner to add features or
enhance its performance. Be warned this usually voids your
warranty. By federal regulation, new scanner models cannot
be easily modified to tune the cellular phone bands.
Modification article files can be copied from several ftp
sites including the /pub/ham-radio/mods directory at:
ftp.cs.buffalo.edu
garfield.catt.ncsu.edu
oak.oakland.edu (IP address 141.210.10.117)
KD4MOJ maintains a scanner modification server for people
without FTP access. You can request a list of scanner
modifications by sending electronic mail with the words GET
INDEX.TXT to FTPmail@exchange.tlh.fl.us
Scanner Repair Shops
Is your scanner broken? Aside from sending the scanner
back to the manufacturer for repair, here are least two
companies which repair scanners:
1. Electronic Repair Centers (telephone 708-455-5105) -
Several people have been pleased with good repair
service from Electronic Repair Centers in Franklin
Park, Illinois. Although they are not authorized to
perform warranty work, this outfit has been repairing
Bearcat scanners for several years. They charge a
flat rate of fixing scanners, and shipping is extra.
Electronic Repair Centers will fix Regency scanners
if they can obtain the parts.
2. G & G Communications (telephone 716-768-8151) - This
family owned company repairs scanners and stocks
parts for several older models. G & G sometimes buys
old scanners, too. They are located at 9247 Glenwood
Drive, LeRoy, NY 14482.
Where Can I Obtain Frequency Information?
To avoid chaos, the FCC licenses two-way radio users and
assigns them specific frequencies. Groups of frequencies
are allocated to specific types of users, so you won't
usually find fire departments using the same frequencies as
taxi drivers, for example.
Scanner enthusiasts can obtain frequency information from
several sources, including books, government microfiche
records, or other listeners.
Books: The most convenient source of fire, police, and
local government frequencies is Gene Hughes' Police Call
Radio Guide, published each year in 9 regional volumes by
Hollins Radio Data, and sold at Radio Shack and larger book
stores.
I also recommend the book, Monitor America, published by
SMB Publishing (now known as Scanner Master Publishing),
and available from Grove Enterprises for about $30. A new |
3rd edition is expected in early 1995. Monitor America
contains several pages of police, fire, local government,
news media, sports, federal government, and commercial
broadcast frequencies for all 50 states. It contains
detailed communications system profiles and precinct maps
for major metropolitan areas. Police and fire radio codes
and unit identifiers unique to local agencies are listed
for several cities. This differs from Police Call, which
gives a more sterile, but uniform treatment of licensees,
listing even the smallest of towns.
Uniden has published several regional directories using the
"Betty Bearcat" name, although there are much better
directories available from Scanner Master (Newton
Highlands, MA, tel. (508)655-6300) for some regions.
The most readily available source of sensitive US
government frequencies is still Tom Kneitel's 168 page Top
Secret Registry of US Government Radio Frequencies. |
Published by CRB Research, the 8th edition is available |
from Grove Enterprises for about $22. Kneitel's book
contains frequency listings for NASA, military, FBI, Secret
Service, DEA, IRS, Border Patrol, arsenals, ammunition
plants, missile sites, and others in the 25 to 470 MHz
range.
Commercial Magazines: Although national in circulation,
local frequency information is sometimes available in
Grove's Monitoring Times (tel. 704-837-9200) and Kneitel's
sensationalistic Popular Communications, (tel. 516-681-
2922). National Scanning Report is a national scanner
magazine published bimonthly and is affiliated with
Uniden's Bearcat Radio Club. It will likely disappoint
experienced scanner hobbyists and is better suited for
beginners. The best scanner frequency lists are often
found in club publications, not commercial magazines, and
are discussed later.
Government Records: Every year, the US Government sells FCC
license information, in the form of microfiche, floppy
disk, and magnetic tape, to the public through the US
Department of Commerce National Technical Information
Service (NTIS). The high cost of buying government records
limits their appeal to hardcore enthusiasts. You can write
for a catalog of FCC Master Frequency Database items to the
NTIS, 5285 Port Royal Road, Springfield, VA 22161.
The FCC has an agreement with PerCon (tel. 716-386-6015), a
private company, to sell FCC license information to the
public on CDROMs. You can buy the full license information
for a multi state region or a less detailed license
database covering the the entire USA on CDROM for about
$100. The new PerCon Spectrum CDROM sells for $29 and
contains a handful of fields for every FCC license in the
US. It works well.
Grove enterprises sells FCC license information on CDROM
for $100. The fields are similar to PerCon's Spectrum
CDROM, but the transmitter and licensee location are
intermixed which makes query results confusing. The first
release has problems with mistakes in the data and
documentation, and I look forward to a new release to
correct these shortcomings.
Over 15% of the FCC licenses, including many fast food
restaurants, contain transmitter latitude and longitude but
specify no transmitter city. To determine the location of
those transmitters requires using the latitude and
longitude information.
As I have already done for dozens of radio enthusiasts and |
companies across the country, I will locate FCC licensed |
and selected FAA transmitter sites in an area of your
choice, and produce a custom report. To make it easy to
locate transmitters, the report includes an 8-1/2" by 11" |
scaled color map marked with transmitter sites and cities
(no streets). I call this innovation RadioMap(TM) service.
It allows you to identify antenna sites (including paging
and cellular phone cell sites) and visualize the
transmitter locations in your neighborhood, near your
office, at an airport, and other places of interest -- from
VLF through microwave. Industry uses RadioMap reports to
survey the "radio environment" prior to installation of
radios and wireless microphones at customer sites.
This is completely different from, and independent of the
Grove Enterprises CDROM.
Ham radio stations are not listed. The RadioMap report
includes frequencies, callsigns, and licensee names. For a
flat fee, you choose the center location, and I choose the
range, depending on transmitter site density. A 5 mile
range (100 sq. mi. area) works well in most suburban areas.
In rural areas, ranges of up to 10 or more miles (400 sq.
mi. area) are possible, while ranges of 1 to 2 miles
produce best results in urban cities, e.g., Manhattan and
downtown Chicago.
I will produce custom RadioMap reports for areas in any of
the 50 states. Send $25.95 (check or money order) for each |
RadioMap report, your name, address, and telephone number,
along with center location (nearest intersection of 2
streets, or latitude & longitude) to: Bob Parnass, 2350
Douglas Road, Oswego, IL 60543. tel. 708-554-3839 6-10 PM
central time. *
Do Your Own Frequency Detective Work
When you try listening to a frequency for the first time,
you'll want to know who you're hearing.
Although FCC rules require radio users to identify their
operations with their assigned call letters, most ignore
the regulation. This often makes it difficult to know who
is transmitting. Moreover, many radios are now being
placed in service illegally, without first obtaining the
required FCC license.
There is a challenge in deriving new spectrum usage
information on your own. Sometimes it requires several
days of listening, taping, and compiling fragments of
information. Other times, the frequency information is
there for the taking - without hassle.
You can approach from two directions:
1. Listen first: Monitor a frequency or frequencies, and
try to determine who's transmitting and what purpose
the channel serves. Once you identify the user, log
the information.
2. Compile first: Take advantage of opportunities, such
as examining the frequency label on a guard's radio,
or reading the FCC license hanging on the "radio
room" wall, to compile frequency lists, then monitor
the listed frequencies to confirm that they are
really in use. Readers are urged to abide by the
rules of good taste and local laws in the quest for
frequency information. Don't trespass, wait for an
invitation.
Most listeners use a combination of both approaches.
You can examine the FCC license on premise. I have found
the actual FCC radio license, complete with frequency
assignments, hanging on the walls of places like the mall
security office or company guard shack. You can examine
the labels on radio equipment. Frequency information is
engraved on labels on the back of many walkie-talkies, or
inside the battery compartment, like in the Motorola HT220
model. Most pagers have labels on the bottom or inside.
Like passwords taped onto terminals, it's not uncommon to
find labels embossed with frequencies or call letters glued
to the front of base stations.
You can make your own opportunities for eyeing the
equipment or take advantage of "open house" events. If
information is displayed publicly, then a reasonable person
could assume it's not government secret. Hobbyists are
urged to exercise a modicum of restraint and good
judgement, however.
How Can I Use Equipment
to Uncover New Frequencies?
If you don't know the exact frequency, but have a general
idea of the range (e.g. 150 - 152 MHz), use your scanner's
"search" mode. Most programmable scanners afford the
ability to search between two frequency limits set by the
user. A few models, like the ICOM R7000/R7100, and R1, and
older Bearcat 250 and Regency K500, have the ability to
automatically store active frequencies found during an
unattended search operation.
To find the frequency of a hotel communications system, one
fellow installed his Bearcat 250 in his car and parked in
the hotel lot, leaving the scanner in the "search and
store" mode. He left the antenna disconnected so the
scanner would only respond to a transmitter in the
immediate vicinity.
Aside from a scanner and antenna, the most useful piece of
equipment for sleuthing is a voice actuated (VOX) cassette
tape recorder. You don't need a high fidelity model or
anything fancy, a Radio Shack CTR-82 will do. It's best to
use a shielded, attenuating cable to feed the scanner audio
into the recorder rather than relying on the recorder's
internal microphone.
VOX recorders allow one to compress a whole day's worth of
monitoring onto a single tape. I often leave a recorder
"armed" and connected to a scanner at home while I am at
the office or doing something else. When call letters are
mumbled, I can play and replay the tape until I hear and
understand them.
Test equipment can aid in the quest for new frequency
information. I've used a spectrum analyzer connected to an
outside antenna, and a frequency counter for close-in work.
Are There Any Scanner Clubs?
One of the best parts of the hobby is sharing it with other
radio buffs. Trading information with other hobbyists
about frequencies, communication systems, and receiving
equipment is more valuable than any pile of magazines.
The world's largest scanner club is the Radio
Communications Monitoring Association (RCMA). Founded in
1975, the RCMA is the "first national and international
organization of monitor radio listeners." There are
several regional chapters which hold regular meetings.
Club dues are $24.00 per year, which includes the monthly
RCMA Journal, which consists of approximately 95 pages.
Although the focus is on VHF and UHF ranges, there is
coverage of HF utility stations below 30 MHz.
Inquiries about RCMA membership should be sent to RCMA
General Manager, P.O. Box 542, Silverado, CA 92676, USA.
All Ohio Scanner Club
A smaller club is the All Ohio Scanner Club. Its bimonthly
publication, The American Scannergram, is about 60 pages
long. Although concentrating on Ohio and the Northeastern
states, there is frequency information from other states,
and plenty of good product reviews and scanning tips.
Annual dues are $18 and more information is available from:
Dave Marshall, Managing Editor
All Ohio Scanner Club,
50 Villa Road,
Springfield, OH 45503.
AOSC questions can also be sent electronically to:
[email protected] or
dave.[email protected].
FidoNet: 1:108/240.0
AOSC also has a MEMBERS & EDITORS Scanner related echo,
AOSCNet, distributed via FTN on 6 BBS systems, and via
Internet Mailing list. For info on the ECHO only, contact:
R.E. Christian, AOSC PA/AOSCNet Founder
PO BOX 12763,
Pittsburgh PA 15241-0763.
FAX: 412-831-5860.
Internet: [email protected]
[email protected]
[email protected]
FidoNet: 1:129/220.0
To receive a file of info on the All Ohio Scanner Club via
Internet send to: [email protected]
In body: get aoscinfo.zip
This will send a UUENCODED info packet to you. The file
contains an outline of the material you will find in the
American Scannergram, the AOSCNet, and an application for
membership. (Note: This file will not be sent back to
*.fidonet.org addresses.)
Chicago Area Radio Monitoring Association
The Chicago Area Radio Monitoring Association (CARMA) is
the foremost club for scanner radio hobbyists in the
northern Illinois area. CARMA was formed from the Chicago
chapter of the Radio Communications Monitoring Association
(RCMA), and we have been meeting since the early 1980s.
Many CARMA members are active in ham radio and GMRS, but
the club is devoted to scanning and scanners.
Meetings are held on Saturdays, most at area restaurants,
about 6 times a year. Although lunch starts at noon, the
meetings begin officially at 1 PM and often run until about
4 PM. You must purchase a lunch since we get the room for
free. Meetings consist of a quick review of club business,
sometimes a special presentation, and a "round table"
discussion/question & answer session. Large quantities of
information and frequency lists are often distributed in
the form of free handouts. Members often sell radio
equipment at the meetings, too.
In addition to regular meetings, there are two CARMA
picnic/field days during which members meet at a park,
erect antennas, eat, and operate scanners from battery
power. CARMA members take organized tours of various
communications facilities in the area.
Club meeting dates and times are published in the CARMA
newsletter, published 6 times a year. A one year
subscription is available by mailing a $15 check, payable
to Kim Moran, to:
The Command Post
attn. Kim & Ted Moran
6143 W. Touhy Avenue
Chicago, IL 60646
Some CARMA members participate on the CARMA computer
bulletin board, run by Will Sperling. If you have a modem
and terminal or computer, you can reach the CARMA BBS by
calling (708)852-1292.
Here is a tentative meeting schedule for 1995. All
meetings will be held on Saturdays at locations announced
in advance.
February 18, 1995 - Westmont Police Dept.
April 15
June 17
August 19
October 14
December 16
Bring a notebook and your appetite.
--
==============================================================================
Copyright 1995, Bob Parnass, AJ9S
AT&T Bell Laboratories - [email protected] - (708)979-5414
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